I. Field
The present invention relates generally to mobile radio telephone systems. More specifically, the present invention relates to systems and methods for controlling the allocation and amount of power that will be transmitted on different channels from a Base Station to a Remote Station in a communication system.
II. Background
It has recently become more common to use spread spectrum techniques, such as code division multiple access (CDMA) techniques, to communicate information over wireless communication systems. For example, CDMA techniques are in wide use for communications between stationary Base Stations and mobile cellular telephones in a cellular telephone network. In accordance with CDMA techniques, several streams of information, typically from different sources, are each encoded (or xe2x80x9cChannelizedxe2x80x9d) using a different code. These codes allow the information to be transmitted over the same frequency band (commonly referred to as a xe2x80x9cCDMA channelxe2x80x9d). Each such Channelized information stream is commonly referred to as a xe2x80x9cCode Channelxe2x80x9d.
It is presently well known that in order to minimize the amount of interference between Code Channels of a CDMA channel, the amount of power that is transmitted on each of the Code Channels must be carefully controlled. Furthermore, it is common for a single amplifier to be responsible for transmitting the entire CDMA channel. When a single amplifier is used to transmit an entire CDMA channel, the more power transmitted in one Code Channel, the less power is available to the other Code Channels. This is because there is typically a limit on the amount of total output power that such an amplifier can provide without undesirably distorting the amplified signals. For at least these reasons, it is important to properly allocate transmit power to each Code Channel in the same CDMA channel.
The described embodiments are directed to a system and method for allocating power to reverse link power control channels. In one aspect, a method for determining the amount of power that is required to transmit power control information from a first station to a plurality of stations is described. The method includes receiving data rate control information from the plurality of stations, the data rate control information indicating the data rate at which power control information is to be transmitted by the first station to the plurality of stations. The data rate control information from each station of the plurality of stations is then adjusted based upon a destination sector that the data rate control information is directed. The amount of power required to transmit the power control information to the plurality of stations is determined from the adjusted data rate control information.
In another aspect, a base station that allocates power to reverse link power control channels is described. The base station includes a receiver configured to receive data rate control information from a plurality of stations, the data rate control information indicating the data rate for which power control information is to be transmitted by the base station to the plurality of stations. The base station also includes a processor, coupled to the receiver, configured to adjust the data rate control information from each station of the plurality of stations based upon a destination sector that the data rate control information is directed and configured to determine from the adjusted data rate control information the amount of power required to transmit the power control information to the plurality of stations.